Trandermal delivery of medicants is limited primarily to the difficult-to-penetrate nature of the stratum corneum layer of skin. The stratum corneum layer forms a barrier that keeps moisture in and keeps practically everything else out. Accordingly, attempts to topically apply a medicant and deliver the medicant across the stratum corneum layer to tissue located beneath it must overcome this barrier property in order to be effect.
The bioavailability of topically applied medicants is typically very low. For example, the bioavailability of topically applied lidocaine is approximately 3%. See, Campbell, et al. J. Pharm. Sci. 91(5), pp. 1343-50 (May 2002). In other words, more than 30 times the desired amount of lidocaine needs to be applied topically for the desired effect. In the case of an expensive medicant or a medicant having various side effects, it is undesirable to require application of such an excess of medicant in order to have the desired effect.
Low-frequency sonophoresis is a known method for enhancing transdermal drug delivery. However, these existing methods employ low-frequencies, low peak intensities, require long application times, or some combination of these to achieve improved transdermal drug delivery.
Microchannels can provide fluid communication between one side of a semi-permeable or impermeable membrane and an opposite side. However, transport of a transport target through a microchannel is slow and limited by diffusion and capillary forces.
Accordingly, a need exists for new systems and methods that overcome the aforementioned shortcomings.